Lifeguards warn people about rip tides at public swimming beaches, such as along ocean beaches. Based upon experience they are trained to visually spot rip tide flows, since rip tides have three basic characteristics that are different from normal waves.
First, rip tide wave patterns are perpendicular to the shore, which is why they rush out to sea so fast and endanger swimmers caught within the pulling power of the rip tide. In contrast, normal ocean waves strike the shore obliquely, and this cushions their impact. Therefore normal ocean waves bounce off the sand at an opposite oblique angle in a flow rate that is rather slow. Lifeguards are trained to spot rip tide water flows going back perpendicular to the shore, as opposed to the oblique configuration of normal ocean beach waves.
Second, the coloration is different. Rip tide waters are generally darker than normal waters.
Third, rip tides may have more surface ripples and texturing.
Related art in non-analogous fields include “Kidnappers beware! New software can nab you”, Machine Design, May 3, 2001 issue, page 48, wherein there is discussed a computerized system which mimics human analysis of handwriting samples; using recognizable features such as shapes and spaces. Furthermore, in “Face identifier uses neural network”, Laser Focus World, May, 2001 issue, page 90, a system is described for training a computer with many examples of images of faces entered into the system with a digital camera, to assist the computer in identifying specific human faces.
However, it is not known to use computer analysis of common ocean rip tide characteristics to predict the presence of an ocean rip tide.